U.S. Pat. No. 1,865,853 relates to the forming of boreholes from an existing wellbore by mechanical means to place a borehole tangentially from an existing wellbore using a rotational bit. Since then, many methods and systems in this area employ hose and nozzle technology to form the boreholes. However, these methods and systems fail to address a number of issues with the process of hydraulically forming boreholes from an existing wellbore.
First, to drill multiple boreholes in different orientations from the same axial location within an existing wellbore, whether the wellbore is vertical, horizontal or deviated, the work string must be rotated from surface using a rig. This process can be time consuming and expensive.
Second, when hydraulic pressure is applied to the work string, the pressure can cause the work string to lengthen due to piston force and shorten due to ballooning. Either of these conditions can be the dominate condition during the same operation depending on the pressure applied. If the pressure is varied during operations, the whipstock attached to the end of the work string can move axially in the wellbore. This axial movement can cause the drill string to be subject to additional bending and friction to remain in the borehole. If the movement is extreme the drill string can be caught in the borehole and potentially be broken off, thereby necessitating an expensive and time consuming retrieval process.
Third, the earth through which the borehole is to be placed is sometimes covered by well casing or liner and the casing or liner must be penetrated to extend the borehole into the earth. Conventional technology does not provide a one-step process for penetrating the casing or liner and placing a borehole.
Fourth, there is limited disclosure in the prior art about the potential uses for the boreholes. More specifically, many existing publications place great emphasis on borehole placement procedures and on the fluid used during the borehole placement process, but do not discuss what the borehole could be used for.
Fifth, existing technologies do not address the orientation and layout of multiple boreholes. It is conventional to place boreholes in vertical wells, which provides very little variety for borehole placement. Many new wells are deviated, horizontal or nearly horizontal, and these wells can stretch extended distances into the earth. The strategic placement of boreholes into these new wells may improve production and enhance the distribution of injection substances.